In the context of the invention the term “polycarbonate compositions” is to be understood as meaning compositions comprising polycarbonate as the main component. The term “polycarbonate” is to be understood here as encompassing both homopolycarbonates and copolycarbonates. These polycarbonates may be linear or branched in the familiar manner. Mixtures of polycarbonates may also be used according to the invention.
Preferably, in the context of the invention “transparent” is to be understood as meaning that the polycarbonate compositions exhibit a transmission, determined to ISO 13468 for a thickness of 4 mm, of at least 86%, more preferably of at least 88% in the range from 400 nm to 800 nm.
Particularly in the case of thin-walled casings, for example for ultrabooks or smartbooks, a low melt viscosity is required in order that components having a uniform wall thickness may be realized.
Bisphenol A diphosphate (BDP) is customarily used for flow enhancement, namely in amounts of up to more than 10 wt % in order to achieve the desired effect. However, this markedly reduces heat resistance.
Diglycerol esters are employed as antistatics in transparent compositions as described in JP 2011108435 A, JP 2010150457 A and JP 2010150458 A for example. JP 2009292962 A describes specific embodiments where the ester has at least 20 carbon atoms. JP 2011256359 A describes diglycerol-ester-containing flame retardant, UV-stabilized antistatic compositions. However, some of the compositions described therein exhibit melt instabilities and polymer degradation on exposure to heat. EP 0994155 describes the addition of full esters of tetraglycerol to a polycarbonate composition.